The goal of the proposed research is to develop chemically-defined serum- free media that will support vigorous proliferation of normal human smooth muscle cells (SMC) and full expression of the contractile phenotype after growth in culture. Exploratory studies will generally be done with SMC from the aorta, but as time permits respiratory, intestinal and other types of SMC will also be studied. Phase I research has already achieved vigorous growth of aortic SMC with 0.5% - 0.55 dialyzed fetal bovine serum and suboptimal growth in a completely serum-free medium. All aspects of the culture system will be carefully examined and optimized as ways are sought to replace the remaining requirement for dialyzed serum. Emphasis will be given to growth factors and other regulatory molecules reported to be mitogenic for SMC, lipoproteins and lipid supplements, avoidance of toxicity that might be neutralized by serum protein and development of a nutritionally complete and well balanced nutrient medium. Recent reports of athe retention of the contractile phenotype in animal cells grown in serum-free media suggest that growth without serum will make similar retention possible in human SMC with only minor adjustment in the culture environment. SMC grown in these media will provide potent model systems for studying environmental signals that lead to abnormal proliferation and loss of the contractile phenotype by SMC in atherosclerosis, as well as physiological mechanisms for control of blood pressure. PROPOSED COMMERCIAL APPLICATION: Clonetics will market the serum-free media and human smooth muscle cells grown in them. These products will allow basic biochemical and pharmaceutical studies on atherosclerosis, hypertension, asthma and other diseases involving smooth muscle to be performed in a precisely controlled environment.